Wave in 4003 4-2-5 Neck

walker · Post by **walker** » Mon Jul 09, 2007 6:45 pm

This thread just caught my eye tonight. I have the same backbow issue with an older 4001 bass. I don't think my neck's condition is as drastic as Bruce's, but similar. With 45-105 gauge strings tuned standard and the rods completely loose, there is a fairly even spread backbow with a slight upward curve around frets 1-5. (Imagine a slight S-curve.) I like my action low to medium-low. The bass plays pretty well above the 8th fret, but below that there is a lot of buzzing, and the E string in particular completely chokes out. I have successfully and easily removed the rods, and they are straight, not curved like Bruce's. The bass has a VERY thin neck & headstock. Given all this info and all the tips outlined here in this thread, is this something that could be remedied with customized rods designed particularly for a backbow, or would the zap with a heat lamp be the appropriate fix? In my gut, the heatlamp approach REALLY makes me nervous. I'd hate to permanently warp the neck beyond repair.

jwr2 · Post by **jwr2** » Mon Jul 09, 2007 6:47 pm

an interesting point is that changing the bass from 4 to 5 strings did not have a bad effect on the neck ... it was a little off before I converted it ... the 4003 neck is plenty strong for 5 strings ...

Lost Coyotes · Post by **Lost Coyotes** » Mon Jul 09, 2007 7:46 pm

I had a bass with the seemingly rare problem neck that bent up from around the second fret to the nut. Made it really hard to get a good setup. I clamped it down properly and heated it with a 75 watt flood lamp, carefully for about 12 hours, making sure it didn't overheat, then let it cool and then unclamped. It seems to have solved the problem, at least for now.

qwezirider · Post by **qwezirider** » Mon Jul 09, 2007 8:23 pm

"I've never used a 75 watt lamp so I have no experience with one, but i would think it would not work since it's only a simple light bulb with no penetrating heat value."

What can I say? After several hours, the neck was clearly warmed on the underside with the lamp over the fingerboard. The cooking hot pad I placed between the neck and table was cooler under the neck than outside the neck profile. So my presumption was the neck was warming throughout and not just surface warming via reflection off the table or hot pad. So far, this evening, the neck is holding to where it was changed over night. I'm just going off the approach described by John Hall in the Rick forum. Maybe I should re-read it, I may have missed something about this having to be a heating lamp in specific.

Again, time should tell if this worked. If not, back to the drawing board. And no, I'm definitely not blaming Jeff's work for the original condition of the neck. After all I've read of his work, nobody has said the conversions would cause structural problems. Which is why I went with his work.

markbass99 · Post by **markbass99** » Tue Jul 10, 2007 12:44 am

None of my 4004 five string conversions have had any issues with the extra pull of the added string. In Bruce's case it would actually help since he had backbow issues. I agree with Bruce in using the lower heat solution over a longer time period, it's not worth taking the chance of messing the neck up with more heat, especially with amateurs like us doing the work.

walker · Post by **walker** » Tue Jul 10, 2007 5:53 am

Mike - How long ago did you do your treatment?

Lost Coyotes · Post by **Lost Coyotes** » Tue Jul 10, 2007 12:49 pm

Mark, I did it Saturday, 3 days ago. It looks as if it's holding.

I somehow expect it to NOT hold, it's been a painful neck in several ways. I need to think positive.

dale_fortune · Post by **dale_fortune** » Tue Jul 10, 2007 2:42 pm

Bruce, I do hope this works for you. That is why I said I have no experience with lamps of that type. I was taught many years ago to use an Infra-Red Heat lamp which does work very quickly. A regular light bulb does get very hot to the touch, and does give off heat. Maybe you could elaborate on the exact procedure: how close to the warped part of the neck did you focus the lamp, how long in one area, did you move the lamp or use more than one lamp, and did you use any type of clamping device to put a reverse bend in the neck? It's hot enough here in Portland today that a heating lamp would not be needed to straighten a neck....

walker · Post by **walker** » Tue Jul 10, 2007 2:52 pm

"It's hot enough here in Portland today that a heating lamp would not be needed to straighten a neck...."

HA! Likewise here in NYC. We're close to 100 degrees in the shade. About a billion % humidity, too.

Back to the heat lamp over a shorter period vs 75 watt incandescent over an all day period - anyone here try both to have an opinion over which is more effective?

dale_fortune · Post by **dale_fortune** » Tue Jul 10, 2007 3:10 pm

Mark, I feel for you guys back there with all that humidity...ours is only 20 percent, so we have a dry heat that is not to bad. As for the Infra-Red lamp, it is a penetrating heat that goes to the depth of the wood in the fingerboard and neck stock. It only takes 10 to 15 minutes with lamps placed 12 inches from the front and back of the neck. Then place your clamping device on to put the proper bend in the neck, let it totally cool for several hours and it stays exactly where it was bent .

Lost Coyotes · Post by **Lost Coyotes** » Tue Jul 10, 2007 3:14 pm

I had seen JHs post first, so that's what I tried. I think, for an amature (me) it's the safe way.
I used a flood-type light, 75 watt about 5" diameter. Place it about 6" away, and very carefully monitored the heat so it didn't get much warmer than you could touch for a few seconds. If I knew what I was doing, I'd have tried Dales's method. For a pro, time is money.

walker · Post by **walker** » Tue Jul 10, 2007 3:41 pm

Thanks so much, you guys. Good info to have. Be that as it may, I'm still going to take the conservative route and let a pro do it, since the bass in question is very old and needs a re-fin, anyway. (That last sentence was aimed at you, Dale!)

qwezirider · Post by **qwezirider** » Tue Jul 10, 2007 4:55 pm

Dale, to elaborate, I used a boring old light from an auto parts store (my dad always called the "trouble lights"), the kind with a wire cage and a hook for hanging. I started with the only regular bendy lamp in the house with a 40 watt bulb and was getting nowhere. So I ran out and got the other light.

I supported the bass on two rather thick books ("The Big Book of Harley-Davidson" and "Dream Bikes"...surely that makes a difference

), one under the nut area, the other under the neck heel. The latter also supported the body well. I then used a large clamp (one of those sliding types on a long bar of metal...don't know the proper name) with plastic coated ends to clamp it all to the dining room table. I'd clamp just enough to see what kind of relief I was creating. Nudge it a bit one way or another until there was a smooth arc.

Then I slowly clamped down for real this time until I had more relief than I thought I would really need for fudge factor. Once set, I placed the lamp face down directly on the neck right next to the clamp at the apex of the relief (about 3:00 p.m.). The wire cage of the lamp kept the bulb about three inches off the finger board.

Kept checking the neck often, less often as the day went on, for signs of being overheated. Poked a fingernail onto the finish to be sure it was not softening (it didn't). After a few hours I could feel heat on the backside of the neck, so I presumed it was radiating through.

At 11:00 p.m. I turned off the lamp and let it cool over night. When taking off the clamp the next morning, I got absolutely no back bow, and bringing the strings back up to tune seemed to make no more relief either.

I'll post a photo later this evening for a clearer idea of what I did.

Then again, perhaps I could've just done this outside as well with 116 degree temps (151 on the sidewalk). If it wasn't for the 4% humidity. I do know the smoker was hot enough to cook without a fire.

I hope I did not come across as questioning your experience, Dale. Far from it. This was just the only technique I'd read about and the lamp you speak of may just be deadly in my hands.

Lost Coyotes · Post by **Lost Coyotes** » Tue Jul 10, 2007 5:01 pm

..."and the lamp you speak of may just be deadly in my hands."
lol!
That's me, man, and I don't got no renter's insurance! If I burn my stuff, it's just gone.

qwezirider · Post by **qwezirider** » Tue Jul 10, 2007 5:58 pm

If I burn mine up I'll just blame Charly for selling me a bum bass. "Dude! You said it could take the heat!"